* Fix improper attachments in replies * Fix import data path * Improve errors * Fix importing attachments directly from zip file * Add some test cases to cover error paths
https://mattermost.atlassian.net/browse/MM-36271 ```release-note We bump the major version to 6.0 ```
* Image logic refactor * Add missing translations * Improve prepareImage * Use iota * Limit image encoder concurrency * Unexport validation methods * Avoid shortening on exported names * Remove unnecessary complexity